違法與合法住宅之價差分析──以基隆河大彎北段商娛區違規使用住宅為例

An Analysis of Price Difference between Illegal and Legal Properties: The Case of Illegal Residential Properties in Commercial and Entertainment District of Taipei City

違規使用住宅理論上會面臨被裁罰的風險，但政府執法程度與是否允許其就地合法化亦會影響其價格變化，本研究主要探討違法與合法住宅之價差變化，並以臺北市中山區大彎北段商娛區的違規使用住宅為例，實證結果顯示大彎北段商娛區違規使用住宅價格相較於南段合法住宅其折價幅度為25.79%，於臺北市政府嚴格裁罰後，折價幅度增加至30.03%，透過差異中之差異法(Difference-in-Difference, DID)，計算其處置效果為-5.47%，驗證違法與合法使用住宅間確實存在明顯的價差，且政府是否嚴格執行裁罰亦會進一步影響兩者的價差，建議政府未來在制定與執行相關政策時應更為審慎，有更完整與長遠的考量。

Under the strict land use regulation, the illegal residential use properties face the risk of being fined. And the intensity of law enforcement and the possibility of being legalized will affect their prices. This study examines the price gap between the illegal and legal residential properties by using the illegal residential properties in the commercial and entertainment district, Dawan North Section, Taipei City. The empirical results show that the price of illegal residential use properties is about 25.79% discount of legal residential use properties. When Taipei City Government strength its law enforcement, the price discount of illegal residential properties increases to 30.03%. The empirical results of Difference-in-Difference (DID) method confirm that stricter law enforcements do have profound -5.47% treatment effect on property prices. The price gap between illegal and legal use properties depends on intensity of law enforcement. Since land use regulation and its law enforcement will affect not only the quality of environment, but also the value of property rights, equality among land owners, and government authority. We recommend that the governments have a more long-term and comprehensive land use planning and stricter enforcement to avoid rent seeking behavior.